Many Implantable Medical Devices (IMDs) collect and store patient data. For example, devices that are adapted to deliver electrical stimulation to a patient for pacing and cardioversion/defibrillation purposes often store data associated with a patient's heart beat. This data can be analyzed by a physician to assess patient health and/or to modify or initiate therapy. Pacing and defibrillation devices may also store information related to blood pressure, heart contractibility, blood chemistry, body temperature, and a host of other physiological indicators that are measured by sensors placed within a patient's body and coupled to the IMD.
Some IMDs do not delivery therapy, and are provided solely to collect and store patient data. For example, the MEDTRONIC Chronicle™ Implantable Hemodynamic Monitor (IHM) employs the leads and circuitry disclosed in commonly-assigned U.S. Pat. Nos. 5,535,752 and 5,564,434 to store EGM and absolute blood pressure values. This data is stored within internal memory within the implantable device, and is periodically transmitted to an external device such as a programmer to be diagnosed by a physician.
Data transferred from an IMD to an external device may be displayed in real-time, and is often also stored for later use and display. If desired, the stored data may be manipulated and processed to obtain further physiological information that may also be displayed.
Physiological data is commonly displayed in a graphical format. One example of a device for graphically displaying data retrieved from an IMD is the Model 9760 programmer manufactured by Medtronic, Inc., Minneapolis, Minn. The Model 9760 programmer is based on a general-purpose microprocessor platform and includes a text and graphics display screen similar to that conventionally used with personal computers. The graphics display screen allows graphical depictions that may include real-time ECG waveform displays. Additionally, the event markers associated with various physiologic and pacing events detected by an IMD can be superimposed upon, or displayed alongside of, the ECG signal.
The display of graphical data collected from an IMD presents several challenges. First, no suitable industry standard is available for the display of such data. As a result, devices are generally equipped with display software that is specifically tailored to the application. The software generally requires a large amount of time and money to implement, and must be supported by a compatible graphics library. Moreover, such software packages must be distributed, installed, and maintained.
One alternative approach to custom software involves the use of web-based viewing software. Such software can be downloaded from a web site to a user system. Since the software is maintained on a central site, costs associated with maintenance and distribution of the software are reduced. However, problems still exist with these types of display systems. For example, the software packages downloaded from a web site must be written in the local language of the new host system. This means that multiple versions of the software must be developed and maintained on the website. This is expensive and cumbersome. Additionally, web-based graphics applications are generally associated with large GIF, JPEG, or PNG files, making them time-consuming to download and execute. Generally, these formats utilize a “one-size-fits-all” approach such that the file size cannot be reduced to take advantage of a smaller application. Finally, current web-based display systems force the user to employ separate views when printing as compared to on-line viewing to control page formatting and to take advantage of printer resolution. The increases development expenses, and is inconvenient to use, requiring the user to execute additional steps to complete a task.
What is needed, therefore, is a high-speed, easy-to-use, system for displaying data collected from implantable medical devices that addresses the drawbacks set forth above, and other disadvantages of prior art systems.